Abstract: A photonic system includes an optical cavity with nonlinear optical characteristics and two or more lasers configured to inject coherent light into the cavity at different frequencies to be locked to the corresponding cavity modes. The cavity, the lasers, and the lock mechanism are configured to correlate the optical properties of the coherent light, wherein the correlation is a classical correlation and/or quantum correlation. Thus, in the photonic system, quantum fluctuations of the two or more lasers can be correlated. The correlation results from the generation of an optical frequency harmonics coincident with the frequencies of the lasers along with simultaneous optical coupling of the lasers and corresponding comb harmonics. As a result of the coupling, the quantum noise of the lasers is correlated so that the frequency noise of the individual lasers can be below the fundamental Schawlow-Townes limit. Method and apparatus examples are described.

Abstract: A dual Lidar-radar sensor instrument based on a photonic implementation. The instrument employs two continuous wave lasers that concurrently provide an optical Lidar signal and a microwave radar signal, via a high bandwidth photodetector, for inherent coherence of Lidar and radar functions for data fusion and other purposes. In illustrative examples, the photonic system is integrated as a photonic integrated circuit (PIC).

Abstract: A photonic system enabling the processing of high frequency microwave, mm-wave, THz signals or other RF signals. The processing may include, e.g., adjusting the frequency, quadrature, and/or power of the signals. In illustrative examples, the system uses a polychromatic light source producing at least two low noise optical emission frequencies that can be independently tuned in a broad frequency range and/or modulated in a broad frequency range using external modulators. An RF input signal is upconverted to one of the optical harmonics of the modulated polychromatic source, processed in the optical frequency domain, and downconverted to the RF domain (at the same or a different RF carrier frequency). The photonic system can be integrated on a planar optical substrate, such as a photonic integrated circuit (PIC). Optical local oscillators are also described for use in the photonic system or for other purposes. Various system, device, and method examples are provided.

Abstract: A photonic synthesizer includes a multifrequency optical source to produce a signal of interest from a pair of lasers, which may be self-injection locked chip lasers. The signal is referenced to a high frequency clock using a photonic mixer/divider based on an electro-optical modulator and a relatively slow photodiode. The electro-optical modulator produces optical harmonics from the beams from the pair of lasers, where one harmonic from the first laser beam and one harmonic from the second laser beam beat on the photodiode. A phase locked control signal is generated for controlling the output frequency of one or both of the two lasers. The output signal of the photonic synthesizer is generated using a relatively fast photodiode based on a difference in frequencies of the pair of lasers. The output signal may be a millimeter wave-band signal. The photonic synthesizer can be formed as a photonic integrated circuit (PIC).

Abstract: A photonic system is described that employs, in some examples, a pair of ultra-low noise semiconductor lasers that produce a low noise electrical signal at the output of a photodetector at a remote location with a frequency set by a frequency interval between the two lasers. The two lasers are phase locked together and mutually locked to a high stability source (such as an atomic clock) at any convenient frequency (e.g., 100 MHz, X-band, Ka-band, W-band, etc.). Upon impinging on the photodetector at the receive location, a combined or merged version of the two laser beams produces a stabilized beat note at the output of the photodetector. Since during transmission both lasers, propagating at the phase velocity, suffer the same frequency deviation due to atmospheric perturbation or motion of the receiver platform, any frequency variations will substantially cancel at the output beat note produced by the photodetector.

Abstract: A photonic synthesizer includes a multifrequency optical source to produce a signal of interest from a pair of lasers, which may be self-injection locked chip lasers. The signal is referenced to a high frequency clock using a photonic mixer/divider based on an electro-optical modulator and a relatively slow photodiode. The electro-optical modulator produces optical harmonics from the beams from the pair of lasers, where one harmonic from the first laser beam and one harmonic from the second laser beam beat on the photodiode. A phase locked control signal is generated for controlling the output frequency of one or both of the two lasers. The output signal of the photonic synthesizer is generated using a relatively fast photodiode based on a difference in frequencies of the pair of lasers. The output signal may be a millimeter wave-band signal. The photonic synthesizer can be formed as a photonic integrated circuit (PIC).

Abstract: A dual Lidar-radar sensor instrument based on a photonic implementation. The instrument employs two continuous wave lasers that concurrently provide an optical Lidar signal and a microwave radar signal, via a high bandwidth photodetector, for inherent coherence of Lidar and radar functions for data fusion and other purposes. In illustrative examples, the photonic system is integrated as a photonic integrated circuit (PIC).

Abstract: A photonic system enabling the processing of high frequency microwave, mm-wave, THz signals or other RF signals. The processing may include, e.g., adjusting the frequency, quadrature, and/or power of the signals. In illustrative examples, the system uses a polychromatic light source producing at least two low noise optical emission frequencies that can be independently tuned in a broad frequency range and/or modulated in a broad frequency range using external modulators. An RF input signal is upconverted to one of the optical harmonics of the modulated polychromatic source, processed in the optical frequency domain, and downconverted to the RF domain (at the same or a different RF carrier frequency). The photonic system can be integrated on a planar optical substrate, such as a photonic integrated circuit (PIC). Optical local oscillators are also described for use in the photonic system or for other purposes. Various system, device, and method examples are provided.

Abstract: One feature pertains to an apparatus that includes apparatus that includes an evanescent field coupler having a first surface that evanescently couples light between the evanescent field coupler and an open dielectric resonator. The apparatus also includes a thin film coating covering at least a portion of the first surface of the evanescent field coupler. The thin film coating is specifically designed so that the thin film coating reflects light of a first wavelength.

Abstract: A coherent lidar system, a method of assembling the system and a vehicle including the system involve a light source to output a continuous wave, and a modulator to modulate a frequency of the continuous wave and provide a frequency modulated continuous wave (FMCW) signal. The system includes a a splitter to split the FMCW signal to two or more paths, and two or more aperture lenses. At least one of the two or more aperture lenses is associated with each of the two or more paths and is configured to obtain a receive beam resulting from a reflection of an output signal obtained from the FMCW signal.

Abstract: A coherent lidar system includes a light source to output a continuous wave, and a modulator to modulate a frequency of the continuous wave and provide a frequency modulated continuous wave (FMCW) signal. The system also includes an aperture lens to obtain a receive beam resulting from a reflection of an output signal obtained from the FMCW signal, and an optical amplifier in a path of the receive beam to output an amplified receive beam. A method of fabricating the system includes arranging a light source to output a continuous wave, and disposing elements to modulate the continuous wave and provide the FMCW signal. The method also includes arranging an aperture to obtain a receive beam resulting from a reflection of an output signal obtained from the FMCW signal, and disposing an optical amplifier in a path of the receive beam to output an amplified receive beam.

Abstract: One feature pertains to an apparatus that includes apparatus that includes an evanescent field coupler having a first surface that evanescently couples light between the evanescent field coupler and an open dielectric resonator. The apparatus also includes a thin film coating covering at least a portion of the first surface of the evanescent field coupler. The thin film coating is specifically designed so that the thin film coating reflects light of a first wavelength.

Abstract: One feature pertains to an apparatus that includes apparatus that includes an evanescent field coupler having a first surface that evanescently couples light between the evanescent field coupler and an open dielectric resonator. The apparatus also includes a thin film coating covering at least a portion of the first surface of the evanescent field coupler. The thin film coating is specifically designed so that the thin film coating reflects light of a first wavelength.

Abstract: A coherent lidar system includes a first light source and a second light source to respectively output a first continuous wave and a second continuous wave, and a first modulator and a second modulator to respectively modulate a frequency of the first continuous wave and the second continuous wave to respectively provide a first frequency modulated continuous wave (FMCW) signal and a second FMCW signal. The system also includes a beam combiner to combine the first FMCW signal and the second FMCW signal into a combined FMCW signal, and one or more aperture lenses to transmit an output signal obtained from the combined FMCW signal and to obtain a return signal resulting from a reflection of the output signal by a target.

Abstract: A coherent lidar system includes a light source to output a continuous wave, and a modulator to modulate a frequency of the continuous wave and provide a frequency modulated continuous wave (FMCW) signal. The system also includes an aperture lens to obtain a receive beam resulting from a reflection of an output signal obtained from the FMCW signal, and an optical amplifier in a path of the receive beam to output an amplified receive beam. A method of fabricating the system includes arranging a light source to output a continuous wave, and disposing elements to modulate the continuous wave and provide the FMCW signal. The method also includes arranging an aperture to obtain a receive beam resulting from a reflection of an output signal obtained from the FMCW signal, and disposing an optical amplifier in a path of the receive beam to output an amplified receive beam.

Abstract: A coherent lidar system, a method of assembling the system and a vehicle including the system involve a light source to output a continuous wave, and a modulator to modulate a frequency of the continuous wave and provide a frequency modulated continuous wave (FMCW) signal. The system includes a a splitter to split the FMCW signal to two or more paths, and two or more aperture lenses. At least one of the two or more aperture lenses is associated with each of the two or more paths and is configured to obtain a receive beam resulting from a reflection of an output signal obtained from the FMCW signal.

Abstract: The disclosure relates in some aspects to a two-point locking system for stabilizing a frequency comb oscillator using at least two optical transitions of the same atomic/molecular sample. In an example, an optical reference sample is provided that is characterized by two or more optical transitions. A coherent light source provides polychromatic coherent light (such as an optical frequency comb). The beams of light, occupying the same spatial mode volume or separated in space, and having frequencies in the vicinity of the optical transitions of the reference sample, interrogate the resonances of the reference sample. Interrogation signals obtained using phase/frequency/amplitude spectroscopy or other spectroscopy techniques are then used to stabilize the frequency harmonics of the light. If the harmonics belong to the same coherent frequency comb, the entire comb becomes stabilized using this procedure. In an illustrative example, a stable atomic optical clock is provided using these techniques.

Abstract: An optical atomic clock utilizing two different laser light sources is described. A source laser is locked to a first optical resonator, which supports a whispering gallery mode for the source laser and generates optical hyperparametric sidebands from the source laser output by multi-wave mixing. A reference laser is locked to an atomic reference via a second optical resonator, and the first optical resonator is locked to the reference laser. Optical parametric sidebands, which are locked to an atomic reference but are generated from a wavelength unrelated to the clock transition of the atomic reference, are coupled out of the first optical resonator to generate an RF signal useful in atomic timekeeping.

Abstract: An optical atomic clock utilizing two different laser light sources is described. A source laser is locked to a first optical resonator, which supports a whispering gallery mode for the source laser and generates optical hyperparametric sidebands from the source laser output by multi-wave mixing. A reference laser is locked to an atomic reference via a second optical resonator, and the first optical resonator is locked to the reference laser. Optical parametric sidebands, which are locked to an atomic reference but are generated from a wavelength unrelated to the clock transition of the atomic reference, are coupled out of the first optical resonator to generate an RF signal useful in atomic timekeeping.

Abstract: A monolithic resonator that has a plurality of mode families is modified so that portions of the resonator have a different index of refraction than other portions of the resonator. This degrades the Q factor of one or more of the mode families, allowing pre-selection of one or more mode families over others.